The research proposed herein is designed to evaluate the use of thin-layer immunoassay (TIA) as a method of drug detection in blood and urine. TIA is an immunoassay which requires no instrumentation or special reagents. Detection of antigen-antibody reactions may be achieved in situ using water vapor. Preliminary studies have demonstrated that morphine may be detected in 14 micro-liters urine samples which have a morphine concentration of 25 ng/ml. Triplicate analyses of several samples may be performed simultaneously in an average time of 10 minutes per sample, at a cost, exclusive of labor, of approximately $0.10 per sample. It is proposed that TIA be evaluated as a method for the detection of morphine, cocaine and delta 9-THC and their metabolites in blood and urine.